The Napoleon Wrasse is found throughout the warm waters of the Red Sea, the Indian and Pacific Oceans. An extremely large fish, it grows to over 2 m and weighs up to 191 kg (420 lb or 30 stone)

Napoleon Wrasse are particularly vulnerable to fishing, as they grow slowly, mature late and are uncommon. They are traded on the live reef food fish market, which serves luxury restaurants in, amongst others, Hong Kong, China, and Singapore. There is evidence of decline throughout its range, but particularly in Southeast Asia. Historical information shows Cheilinus undulatus was common in the 1950s and 1960s, and that declines have coincided with increased fishing activity.

The wrasse spawns in aggregations that can easily be targeted by fishers and hence are particularly vulnerable to overfishing at the times and places at which reproduction occurs. It has been well-documented that spawning aggregations in several other reef fish species are particularly vulnerable to being overfished.

To compound its problems, the species changes sex from female to male, which, if a fishery selects for larger fish, may make it even more vulnerable to over-fishing. It is estimated that less than 1% reach maturity as males. However, the most preferred market size for this fish as food is 'plate-sized' – between about 30-60 cm total length. Plate-sized fish are typically sexually immature since sexual maturity occurs at about 50 cm. This means that large numbers of sexually immature fish are removed from the wild for the live reef food fish trade. If young fish are being removed before they can produce the next generation, how can populations replace themselves and recover from fishing?